46 research outputs found
Coastal waters of a marine protected area of the Bijagós Archipelago, West Africa, shelter juvenile fishes of economic and ecological importance
In many marine ecosystems small pelagic fish exert a crucial role in controlling the dynamics of the
community, mainly due to their high biomass at intermediate levels of the food web. These fish use
coastal marine ecosystems as nursery areas, but also to forage and to avoid predation or competition.
We studied spatial, seasonal, lunar and diel variations in a coastal fish community from a marine
protected area of the Bijagós Archipelago, Guinea-Bissau. Fish were sampled with 46 beach seine net
sessions in 2015 and 2016. A total of 35 fish species of 25 families were captured. Fish abundance
varied between years and seasons, with a higher abundance in the dry season, but not by lunar tide.
Nonetheless, the community composition was broadly similar over the seasons, among islands and
between lunar tides. Clupeidae, Haemulidae and Gerreidae were the most abundant fish families.
Sardinella maderensis highly dominated the captures throughout the year, with catches much higher
than any other species. The differences in abundance between seasons and years may be related with
movements to or from the shore due to feeding activity or to avoid predation, or else to differences in
recruitment between years. There were no significant diel differences in species richness and diversity,
although higher numbers of fish were captured during daytime. For most species the majority of
individuals captured were immature, highlighting the importance of the archipelago as nursery area
for several species. These small pelagics, and particularly Sardinella maderensis, represent the main
prey for several marine predators. Thus, the conservation of such fish species may be key for the
management of the Bijagós Archipelago.Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio
Red, gold and green: microbial contribution of Rhodophyta and other Algae to Green Turtle (Chelonia mydas) Gut Microbiome
The fitness of the endangered green sea turtle (Chelonia mydas) may be strongly affected
by its gut microbiome, as microbes play important roles in host nutrition and health. This study
aimed at establishing environmental microbial baselines that can be used to assess turtle health under
altered future conditions. We characterized the microbiome associated with the gastrointestinal tract
of green turtles from Guinea Bissau in different life stages and associated with their food items, using
16S rRNA metabarcoding. We found that the most abundant (% relative abundance) bacterial phyla
across the gastrointestinal sections were Proteobacteria (68.1 ± 13.9% “amplicon sequence variants”,
ASVs), Bacteroidetes (15.1 ± 10.1%) and Firmicutes (14.7 ± 21.7%). Additionally, we found the
presence of two red algae bacterial indicator ASVs (the Alphaproteobacteria Brucella pinnipedialis with
75 ± 0% and a Gammaproteobacteria identified as methanotrophic endosymbiont of Bathymodiolus,
with <1%) in cloacal compartments, along with six bacterial ASVs shared only between cloacal and
local environmental red algae samples. We corroborate previous results demonstrating that green
turtles fed on red algae (but, to a lower extent, also seagrass and brown algae), thus, acquiring
microbial components that potentially aid them digest these food items. This study is a foundation
for better understanding the microbial composition of sea turtle digestive tracts.info:eu-repo/semantics/publishedVersio
Red, Gold and Green: Microbial Contribution of Rhodophyta and Other Algae to Green Turtle (Chelonia mydas) Gut Microbiome
The fitness of the endangered green sea turtle (Chelonia mydas) may be strongly affected by its gut microbiome, as microbes play important roles in host nutrition and health. This study aimed at establishing environmental microbial baselines that can be used to assess turtle health under altered future conditions. We characterized the microbiome associated with the gastrointestinal tract of green turtles from Guinea Bissau in different life stages and associated with their food items, using 16S rRNA metabarcoding. We found that the most abundant (% relative abundance) bacterial phyla across the gastrointestinal sections were Proteobacteria (68.1 ± 13.9% “amplicon sequence variants”, ASVs), Bacteroidetes (15.1 ± 10.1%) and Firmicutes (14.7 ± 21.7%). Additionally, we found the presence of two red algae bacterial indicator ASVs (the Alphaproteobacteria Brucella pinnipedialis with 75 ± 0% and a Gammaproteobacteria identified as methanotrophic endosymbiont of Bathymodiolus, with <1%) in cloacal compartments, along with six bacterial ASVs shared only between cloacal and local environmental red algae samples. We corroborate previous results demonstrating that green turtles fed on red algae (but, to a lower extent, also seagrass and brown algae), thus, acquiring microbial components that potentially aid them digest these food items. This study is a foundation for better understanding the microbial composition of sea turtle digestive tracts.info:eu-repo/semantics/publishedVersio
Satellite tracking and field assessment highlight major foraging site for green turtles in the Banc d'Arguin, Mauritania
There is a remarkable paucity of estimates of the numeric importance of sea turtles at foraging grounds. The Banc d'Arguin (BA) is a vast shallow marine area off the coast of Mauritania, known as a site of world importance for coastal migratory birds and other biodiversity, including extensive seagrass beds. We sampled foraging green turtles on the BA, and extensively tracked adult female green turtles from the Bijagós archipelago, the only significant nesting aggregation within 3000 km of the BA, to estimate the abundance of this foraging aggregation. Additionally, we used a demographic simulation to support our findings. Based on satellite tracking of adult females (n = 46), we estimate that 50 % of the nesting population from the Bijagós migrate to the BA post-nesting. We combine data on numbers nesting in the Bijagós with information on proportion migrating to the BA in the same years to conservatively estimate that 8285 adult female green turtles forage at this site. We also estimate that adult females represent only 5.6 % of the green turtles in the BA, implying that the number of turtles there is of the order of 150,000 individuals. Most of the BA enjoys effective protection as part of the Parc National du Banc d'Arguin where significant fisheries regulations are well enforced by a marine surveillance program. We show that the BA is one of the major foraging sites for green turtles nesting in the Bijagós and a site of critical importance for immature and adult green turtles in a global context.Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio
Industrial fishing near West African Marine Protected Areas and its potential effects on mobile marine predators
Marine Protected Areas (MPAs) are increasingly implemented to facilitate the conservation of marine biodiversity and key-habitats. However, these areas are often less effective to conserve mobile marine species like elasmobranchs (i.e. sharks and rays). Industrial fishing near MPA borders possibly impacts vulnerable species utilizing these protected areas. Hence, we aimed to study spatiotemporal patterns of industrial fisheries near MPAs, in relation to the bycatch of elasmobranchs. Specifically, we analyzed the spatiotemporal fishing effort within the West African region, mapped fishing effort in the direct vicinity of the Parc National du Banc d’Arguin (Mauritania) and the Bijagós Archipelago (Guinea Bissau) and compared the seasonal overlap between elasmobranch bycatch and fishing effort near these MPAs. We combined Automatic Identification System data and local fisheries observer data, and determined fishing effort for each gear type and compared this with bycatch of elasmobranchs. We found that industrial fishing effort was dominated by trawling, drifting longlines and fixed gear types. Although no industrial fishing was observed within both MPAs, 72% and 78% of the buffer zones surrounding the MPAs were fished for the Banc d’Arguin and Bijagós respectively. Within the Banc d’Arguin buffer zone, trawling and drifting longlines dominated, with longlines mainly being deployed in fall. In the Bijagós buffer zone, trawling and fixed gears were most prevalent. Fisheries observer data for Mauritania showed that elasmobranch catches increased during the most recent sampling years (2016 to 2018). Elasmobranch catches within the waters of Guinea Bissau peaked in 2016 and decreased in the following two years. Seasonal patterns in elasmobranch bycatch within the waters of both countries are likely caused by increased catches of migratory species. Catches of rays peaked in May and June for Mauritania, and in October for Guinea Bissau. Shark catches were highest in February and July in Mauritanian waters, and in May and October in the waters of Guinea Bissau. Our study indicates that industrial fisheries near the border of ecologically important MPAs may have potentially major implications for ecosystem functioning by the removal of (migratory) predatory species
Seagrass connectivity on the west coast of Africa supports the hypothesis of grazer-mediated seed dispersal
Population connectivity influences the distribution of genetic diversity and divergence
along a species range, as the likelihood of extinction or differentiation increases in isolated
populations. However, there is still poor understanding of the processes mediating interpopulation dispersal in marine species that are sessile and lack planktonic life stages. One
such case is the seagrass species Halodule wrightii, which produces basal seeds,
although detached plants can drift. Along the tropical western coast of Africa, this
species occurs in distant discontinuous habitats, raising the question of how
interpopulation dispersal is mediated. The species is a key source of ecosystem
functions including feeding large migratory grazers. This study aims to infer whether
genetic differentiation of the seagrass H. wrightii along the western coast of Africa
supports a hypothesis of predominant transportation of rafting seagrass by ocean
currents, versus the hypothesis of biotic vectors of dispersal. Additional hypotheses
were addressed concerning range-wide clonality and genetic diversity, assessed with
microsatellite markers on populations of the west coast of Africa from Mauritania to
Angola. Population genetic diversity and structure were compared with predictions from
biophysical models of dispersal by oceanographic currents. The genetic data revealed low
divergence among most populations, in strong contrast with predictions of very low
probability of connectivity mediated by currents along the western African coastline.
Moderate to high genotypic diversity showed important seed recruitment, but genetic and
genotypic diversities were lower at range edges. Populations north and south of the
equator were differentiated, and remarkably, so were neighboring equatorial populations despite their proximity. These results reveal independent sources of colonization of
meadows in these islands, which are major habitat for migratory grazing green turtles,
also supporting the hypothesis of biotically mediated seed transport. The importance of
seagrass for conservation of endangered macrofauna has been widely reported; here we
report evidence supporting the reciprocal role, that macrofauna protection can also plays
a role in long-term survival and reproductive success of seagrass.Fundação para a Ciência e Tecnologia - FCTinfo:eu-repo/semantics/publishedVersio
Avian haemosporidians in the cattle egret (Bubulcus ibis) from central-western and southern Africa: high diversity and prevalence
We described the geographic distribution of 82 haemosporidian lineages (Plasmodium, Haemoproteus, and Leucocytozoon) in the cattle egret sampled in five countries in central-western and southern Africa. Seventy-three lineages have not previously been reported. We determined the prevalence of three haemosporidians in the samples. We investigated the influence of the internal environment of the host and environmental variables on the Plasmodium diversity and whether environmental variables may explain spatial variations in the prevalence of Plasmodium. We screened DNA from 509 blood samples from nestlings in 15 African colonies for infection by sequencing the cytochrome b gene of parasites. The molecular phylogenetic analysis was performed using Bayesian methods and including sequences from the MalAvi and GeneBank databases. We found 62 new Plasmodium lineages in a clade with MYCAME02, which is a lineage described in waterbirds and recently identified in birds of prey as Plasmodium paranucleophilum. Two Haemoproteus lineages identified in cattle egret formed a distinct group with Haemoproteus catharti and MYCAMH1 (Haemoproteus spp.). Seven Leucocytozoon lineages found in the cattle egret clustered with Leucocytozoon californicus. We found different Plasmodium diversities among the colonies sampled, demonstrating that the internal environment of the host is not the primary determinant of diversity. A linear mixed-effects multivariate model showed that precipitation was positively associated with Plasmodium diversity when controlling for the effects of temperature, colony composition (mixed and non-mixed species) and country. Moreover, a generalized mixed model showed that temperature was positively associated with the prevalence of Plasmodium when controlling for precipitation, elevation and country. We conclude that the cattle egret is a good model for future haemosporidian studies, as we found a significant number of new lineages in this host, which occupies regions with different climate characteristics where environmental variables exert an influence on the diversity and prevalence of Plasmodium
Envisioning a resilient future for biodiversity conservation in the wake of the COVID-19 pandemic
NE/T010401/1 UIDB/04647/2020 UIDP/04647/2020As the COVID-19 pandemic continues to affect societies across the world, the ongoing economic and social disruptions are likely to present fundamental challenges for current and future biodiversity conservation. We review the literature for outcomes of past major societal, political, economic and zoonotic perturbations on biodiversity conservation, and demonstrate the complex implications of perturbation events upon conservation efforts. Building on the review findings, we use six in-depth case studies and the emerging literature to identify positive and negative outcomes of the COVID-19 pandemic, known and anticipated, for biodiversity conservation efforts around the world. A number of similarities exist between the current pandemic and past perturbations, with experiences highlighting that the pandemic-induced declines in conservation revenue and capacity, livelihood and trade disruptions are likely to have long-lasting and negative implications for biodiversity and conservation efforts. Yet, the COVID-19 pandemic also brought about a global pause in human movement that is unique in recent history, and may yet foster long-lasting behavioural and societal changes, presenting opportunities to strengthen and advance conservation efforts in the wake of the pandemic. Enhanced collaborations and partnerships at the local level, cross-sectoral engagement, local investment and leadership will all enhance the resilience of conservation efforts in the face of future perturbations. Other actions aimed at enhancing resilience will require fundamental institutional change and extensive government and public engagement and support if they are to be realised. The pandemic has highlighted the inherent vulnerabilities in the social and economic models upon which many conservation efforts are based. In so doing, it presents an opportunity to reconsider the status quo for conservation, and promotes behaviours and actions that are resilient to future perturbation. A free Plain Language Summary can be found within the Supporting Information of this article.publishersversionpublishe
Developing an Evidence-Based Coexistence Strategy to Promote Human and Wildlife Health in a Biodiverse Agroforest Landscape
UIDB/04038/2020
UIDP/04038/2020Agroforest mosaics represent one of the most extensive human-impacted terrestrial systems worldwide and play an increasingly critical role in wildlife conservation. In such dynamic shared landscapes, coexistence can be compromised if people view wildlife as a source of infectious disease. A cross-disciplinary One Health knowledge base can help to identify evolving proponents and threats to sustainable coexistence and establish long-term project goals. Building on an existing knowledge base of human–wildlife interactions at Cantanhez National Park (NP), Guinea-Bissau, we developed a causal pathway Theory-of-Change approach in response to a newly identified disease threat of leprosy in the Critically Endangered western chimpanzee (Pan troglodytes verus). The goals of our project are to improve knowledge and surveillance of leprosy in humans and wildlife and increase capacity to manage human–wildlife interactions. We describe the core project activities that aim to (1) quantify space use by chimpanzees across Cantanhez NP and determine the distribution of leprosy in chimpanzees; (2) understand the health system and local perceptions of disease; and (3) identify fine-scale risk sites through participatory mapping of resources shared by humans and chimpanzees across target villages. We discuss the development of a biodiversity and health monitoring programme, an evidence-based One Health campaign, and a One Health environmental management plan that incorporates the sharing of space and resources, and the disease implications of human–non-human great ape interactions. We demonstrate the importance of multi-stakeholder engagement, and the development of strategy that fully considers interactions between people, wildlife, and the environment.publishersversionpublishe
Dietary flexibility of western red colobus in two protected areas with contrasting anthropogenic pressure
Food distribution and abundance can affect intra- and inter-dietary variation in non-human primates, influencing feeding ecology and altering behaviour. Natural and/or human-induced actions can influence the dynamics between primates and the environment, with associated impacts on socio-ecology and demography. This relationship in anthropogenic landscapes, however, is poorly understood. Here, we use DNA metabarcoding to obtain high resolution dietary diversity data, and multivariate generalised linear models to investigate variation in the diet of this threatened primate. We characterise the diet of the western red colobus (Piliocolobus badius) in both the better preserved Gola Rainforest National Park (GRNP, Sierra Leone), and in the fragmented forests of Cantanhez National Park (CNP, Guinea-Bissau), and evaluate biological, ecological and temporal differences. Dietary plant species richness was high in both protected areas, and the type of plants consumed varied significantly across seasons, space, and time. Although we identify dependence on a few key plants, red colobus in CNP consumed a higher average number of plant taxa than in GRNP, and 11% of the diet consisted of cultivated foods (e.g. mango). This is the first time a molecular approach has been used to investigate red colobus diet, and reveal dietary flexibility in degraded forests. Predicting the consequences of dietary change on long-term population persistence, however, remains a significant knowledge gap. Nevertheless, our results provide critical information to inform targeted regional conservation planning and implementation